JPH05280882A - Heat dissipating fin - Google Patents

Abstract

PURPOSE:To obtain a heat dissipating fin in which a heat transfer amount of a pin fin group can be obtained in a high efficiency state by reducing waste of pressure loss. CONSTITUTION:An arranging interval (a) of a pin fin group 11, in which needlelike thermal conductors 13 are arranged in a rectangular state, perpendicular to an air flow is set to a range of 1-1.5 times as large as a length of an outer periphery of the conductor 13. A volume occupied by the conductors 13 is set to 20% or less of an envelope volume of the group 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiator fin used for radiating heat from various radiators and heat exchangers including air conditioners, chips of integrated circuits such as computers, and other heating elements.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for high-performance heat radiation fins due to advanced cooling technology for integrated circuit chips, etc., which is accompanied by the speeding up and downsizing of computers, and is suitable for miniaturization of the heat transfer surface. Attention has been focused on a radiation fin that is formed by arranging a large number of needle-shaped heat conductors (pin fins) having a polygonal cross section in parallel with each other in a rectangular shape.

FIG. 3 shows a pin fin group 1 of this type of heat radiation fin. The pin fin group 1 has a structure in which a large number of needle-shaped heat conductors 3 are erected on a substrate portion 2 in a rectangular array with a space therebetween. As shown in the enlarged view of FIG. 4, each of the needle-shaped heat conductors 3 has a quadrangular cross section and a fine prismatic shape with one side dp of about 0.2 mm, and is high in order to increase the heat transfer amount (heat dissipation amount). They are arranged in a density. That is,
The vertical and horizontal arrangement intervals (pitch) p are set to be narrow.

[0004]

By the way, in the above-mentioned conventional fin fin type heat radiation fin, in order to increase the amount of heat transfer, a large number of prismatic needle-shaped heat conductors 3 are arranged in a high density rectangular shape. It constituted the pin fin group 1. That is, the vertical and horizontal arrangement intervals (pitch) p are determined by trial and error by giving priority to the amount of heat transfer. As a result, the array interval p is 1/2 or less of the outer peripheral length of the cross section of the needle-shaped heat conductor 3 (twice or less of the length dp of one side of the prism) under the present circumstances. And the heat transfer between the needle-shaped heat conductors 3
As is clear from the relationship with the pressure loss characteristics, the pressure loss of the air blown from the blower was extremely large, and there was a problem of poor efficiency as a whole evaluation.

The present invention has been made to solve the above problems, and an object thereof is to maintain a high heat transfer amount in the pin fin group and reduce unnecessary pressure loss, which is very efficient. It is to provide a radiation fin that can obtain a heat transfer effect.

[0006]

The heat radiation fin of the present invention comprises:
In order to achieve the above-mentioned object, the arrangement interval of at least one direction of a large number of pin-shaped fin-shaped heat conductors having a polygonal cross-section is defined as 1 perimeter of the cross-section of the needle-shaped heat conductors. It is characterized by being set within the range of up to 1.5 times.

[0007]

In the radiating fin having the above-described structure, the arrangement interval of the needle-shaped heat conductors of the polygonal cross section of the pin fin group is in the range of 1 to 1.5 times the outer peripheral length of the cross section of the needle-shaped heat conductors. If it is used in the direction perpendicular to the flow, the heat transfer amount of the pin fin group is relatively high, as can be seen from the relationship between the arrangement interval of the needle-shaped heat conductors and the heat transfer / pressure loss characteristics by the parameter test described later. While maintaining it, wasteful pressure loss can be greatly reduced, a highly efficient heat transfer effect can be obtained overall, and a highly efficient radiator or heat exchanger can be realized.

In a conventional product in which the needle fin heat conductor of the pin fin group has an arrangement interval in the direction perpendicular to the air flow of less than one time the outer peripheral length described above, a large heat transfer performance can be obtained, but the pressure If the loss increases at a larger rate and the overall evaluation becomes less efficient, and conversely becomes greater than 1.5 times the outer circumference length, the pressure loss will be small but the amount of heat transfer will significantly decrease, leading to poor heat dissipation performance.

Further, as described above, the arrangement interval in the direction perpendicular to the air flow of the needle-shaped heat conductor having the polygonal cross section of the pin fin group is 1 to 1.5 times the outer peripheral length of the cross section of the needle-shaped heat conductor. In the radiating fins having the range configuration, the volume occupied by many needle-shaped heat conductors of the pin fin group is set to 20% or less of the envelope volume of the pin fin group, that is, the needle-shaped heat conductor air flow direction. By making the arrangement interval of 0.35 times or more of the outer peripheral length of the cross section of the needle-shaped heat conductor, the pressure loss due to the occurrence of an abnormal disturbance state of the air flow as in the case of a larger arrangement distance than this It is possible to prevent an excessive increase, resulting in a more efficient and optimal array structure.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the heat radiation fin of the present invention will be described below with reference to the drawings. First, FIG. 1 is a plan view in which a part of the pin fin group 11 of the heat dissipation fin of the present invention is partially omitted. The pin fin group 11 is a quadrangular cross section manufactured by applying an etching technique using a thin copper plate as a material and one side dp is 0.2 mm. A large number of fine prismatic needle-shaped heat conductors 13 are arranged in a rectangular shape with an interval therebetween.

The needle-shaped heat conductor 13 of the pin fin group 11
Array spacing (array spacing a in the direction perpendicular to the air flow,
The arrangement interval b) in the air flow direction is set to the optimum value (the most efficient value) clarified from the relationship with the heat transfer / pressure loss characteristics of the parameter test described later. That is, the arrangement interval a in the direction perpendicular to the air flow of the needle-shaped heat conductor 13 of the pin fin group 11 is 1.25 times the outer peripheral length of the cross section of the needle-shaped heat conductor 13, that is, the length of one side of the prism. 5 times dp (a
/Dp=5.0), the arrangement interval b in the air flow direction is 0.5 times the outer circumferential length of the cross section of the needle-shaped heat conductor 13, that is, 2.0 times the length dp of one side of the prism (b / dp = 2.0). ), The volume ratio of these needle-shaped heat conductors 13 to the envelope volume of the pin fin group 11 is 20% or less.

The arrangement interval (pin pitch) a having such a configuration
Described below is an experimental example that is based on the fact that /dp=5.0 and b / dp = 2.0 are the most efficient. The pin fin group tested in this experiment has a quadrangular cross section and a fine prismatic needle-shaped heat conductor 13 having a side dp of about 0.2 mm and an array spacing a / dp in the direction of orthogonal to the air flow of 3.0 to 7.0. Then, the arrangement interval b / dp in the flow direction was systematically changed in the range of 1.5 to 6.0, and a parameter test was performed using an automatic measurement system for heat transfer characteristics based on the improved single blow method.

FIG. 2 shows the relationship between the various arrangement intervals a / dp, b / dp of the needle-shaped heat conductor obtained from the test results and the heat transfer / pressure loss characteristics. Here, the vertical axis represents the heat transfer amount E per unit envelope volume / unit temperature difference of the pin fin group.
And the horizontal axis represents the blasting power (proportional to the pressure loss of the pin fin group) P per unit envelope volume of the blower. In both cases, the approaching flow velocity U1 of air to the pin fin group is LS
It is common when used as a radiator of I etc. 2
This is the case of m / s. The definitions of E and P are as follows.

E = hm · A / V; P = ΔP · U1 · Az / V hm: Average heat transfer amount (not including fin efficiency), A: Heat transfer area, V: Pin fin envelope volume, Az: Pin fin group Inlet area (duct cross-sectional area) In the figure, △ is a / dp = 3.0, □ is a / dp = 4.0, ▽ is a / dp = 5.0, ◇ is a / dp = 6.0, and ○ is a / dp = 7.0.
In each case, the array spacing in the direction perpendicular to the air flow is shown. In addition, the numerical value in [] in the figure shows the array interval b / dp value in the air flow direction.

Here, since a high-performance radiating fin has a high heat transfer performance and a small pressure loss at the same time, in this figure, P has a small value and E has a large pin arrangement interval. Can be said to be the pin fin group with the best overall performance. From this point of view, when Δ / a = dp = 3.0, where the arrangement interval is narrow, the heat transfer performance is high, but the pressure loss is much higher. On the other hand, when the arrangement spacing is wide and a / dp = 7.0, the heat transfer surface has a low density, and the heat radiation amount per unit volume is considerably low. Therefore, ▽ in the middle of this data
It can be said that the mark a / dp = 5.0 is the best array pitch structure in terms of overall performance. When a / dp = 5.0 marked with ▽ and a / dp = 6.0 marked with ◇, the arrangement interval b / dp in the air flow direction
Change has a small effect on overall performance, but b / dp is 2
It can be seen that the overall performance is higher, although there are some cases where it is set to about 4.5. This is △ mark a / dp = 3.0
It also applies when a / dp = 4.0 marked with or.

Looking at the alternate long and short dash line connecting the points where the overall performance is high at these various arrangement intervals Δ, □, ▽, ◇, ○, the inflection point is just around the a / dp = 5.0 marked with ▽. You can see that there is H. The ones marked with □ and △ above the inflection point H tend to increase the amount of heat transfer, but the pressure loss tends to increase, and the ones marked with ◇ and ○ below the inflection point H, on the other hand, show the pressure. Although the loss decreases, the amount of heat transfer tends to decrease in proportion to it. In other words, there is exactly the ▽ mark near the inflection point H a / dp =
5.0 and b / dp = 2 to 4.5 pin pitch (Fig. 1
It can be said that the arrangement structure of the pin fin group 11 shown in 1) is a highly efficient heat radiating fin that has the best overall performance and has a small blowing power and a large amount of heat transfer.

When actually used as a radiator of an LSI or the like, in this data, a part of a / dp = 4.0 of the upper square centered on the a / dp = 5.0 of the ▽ mark and a part of the lower side ◇ marked a /
The one with dp = 6.0 is an efficient range, and it is possible to keep the amount of heat transfer in the pin fin group high and reduce unnecessary pressure loss. Also in this case, the arrangement interval b / dp = 2 to 4.5 in the air flow direction (the volume ratio of the needle-shaped heat conductor to the envelope volume of the pin fin group is 20% or less) is appropriate.

In the above-mentioned embodiment, the arrangement interval a / dp in the direction perpendicular to the air flow of the needle-shaped heat conductor 13 is 4.0 to 6.0 times the length of one side of the rectangular prism having a square cross section. Considering the case of using a needle-shaped heat conductor having a polygonal cross section such as a pentagon, 1 to 1.5 of the outer peripheral length of the cross section of the needle-shaped heat conductor is considered.
It is good to set it as double.

[0019]

Since the radiating fin of the present invention is constructed as described above, the heat transfer amount of the pin fin group can be efficiently obtained in a high state without causing unnecessary pressure loss, and the overall performance is excellent. It is possible to realize a heat radiator or a heat exchanger.

[Brief description of drawings]

FIG. 1 is an enlarged plan view in which a pin fin group is partially omitted, showing an embodiment of a heat dissipation fin of the present invention.

FIG. 2 is an explanatory diagram showing, in the form of a graph, measurement results of a parameter experiment showing an optimum arrangement of needle-shaped heat conductors of a pin fin group of a radiation fin of the above-mentioned embodiment.

FIG. 3 is a schematic configuration diagram showing a pin fin group of a general radiation fin.

FIG. 4 is an enlarged plan view showing a state of arrangement of a conventional pin fin group, with some parts omitted.

[Explanation of symbols]

11 ... Pin fin group, 13 ... Needle-like heat conductor, a ... Arrangement interval in the direction perpendicular to the air flow, b ... Arrangement interval in the air flow direction.

Claims (2)

[Claims] 1. A radiation fin comprising a pin fin group formed by arranging a plurality of needle-shaped heat conductors having a polygonal cross section in a rectangular shape with an interval between each other. A radiating fin, wherein the arrangement interval in at least one direction is set within a range of 1 to 1.5 times the outer peripheral length of the cross section of the needle-shaped heat conductor. 2. The radiating fin according to claim 1, wherein the volume occupied by the needle-shaped heat conductor of the pin fin group is 20% or less of the envelope volume of the pin fin group.